PET/CT in cancer research: from preclinical to clinical applications.

The identification of genetic and biochemical mechanisms underlying tumor growth and progression along with the unraveling of human genoma provided a plethora of new targets for cancer detection, treatment and monitoring. Simultaneously, the extraordinary development of a number of imaging technologies, including hybrid systems, allowed the visualization of biochemical, molecular and physiological aberrations linked to underlying mutations in a given tumor. In vivo evaluation of complex biological processes such as proliferation, apoptosis, angiogenesis, metastasis, gene expression, receptor-ligand interactions, transport of substrates and metabolism of nutrients in human cancers is feasible using PET/CT and radiolabeled molecular probes. Some of these compounds are in preclinical phases of evaluation whereas others have been already applied in clinical settings. Here we provide prominent examples on how some biological processes and target expression can be visualized by PET/CT in animal tumor models and cancer patients for the noninvasive detection of well-known markers of tumor aggressiveness, invasiveness and resistance to treatment and for the evaluation of tumor response to therapy.

Molecular imaging of tumor microenvironment: challenges and perspectives.

Tumor microenvironment consists of a number of components including host resident stromal cells, infiltrating immune cells and extracellular matrix. The architecture surrounding tumor cells is not static but is subjected to a continuous remodeling in response to the dynamic interplay between tumor and stromal cells and to the production of extracellular proteases. In addition all these microenvironmental components along with cancer cells are exposed to abnormal physiologic conditions such as hypoxia and acidic extracellular pH that may induce both adaptive and constitutive changes in cancer and stromal cells. In this review, we will primarily focus on the possibility to visualize in vivo tumor microenvironment components and conditions as well as interactions with cancer cells. The major goal is to highlight the difficulties and the opportunities of this approach and how each imaging technology helps to overcome specific challenge.

[Anti-platelet-aggregation drugs and atherosclerosis]. / Antiaggreganti piastrinici ed aterosclerosi.

The relationship between hyperlipidaemia and thrombophilic state in atherosclerosis was appraised by evaluation of platelet aggregation according to Breddin in 20 patients with clinically established atherosclerosis, 10 normal controls, and 22 subjects taken from the average population of a medical department aged 12-58 yr with no history of atherosclerosis. Normal screening for the disease was carried out in all patients. Drugs inhibiting platelet-aggregation were given to all subjects in Breddin's 3rd or 4th stage. A relationship was noted between Breddin stage and the seriousness of atherosclerosis, while the former was a pointer to thrombophilic states. The drugs administered were able to reverse the aggregation stage.